Transformer connection.



K. SCHMIDT.

TRANSFORMER commcmom.

APPLICATION FILED AUG. 25, 1311 1 ,072,042. Patented Sept. 2, 1913,

Witnesses: Inventor Karl Schmidt,

M4 K b d/(Mgw;

H is Attorney.

UNITED STATES PA'IENT OFFICE.

KARL SCHMIDT, OF HERMSDORF, NEAR BERLIN, GERMAN Y, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TRANSFORMER CONNECTION.

Patented Sept. 2, 1913.

1 application filed August 25, 1911. Serial N 0. 646,007.

To all whom it may concern:

Be it known that I, KARL SCHMIDT, a subject of the Emperor'of Germany, residing at Hermsdorf, near Berlin, Germany, have invented certain new and useful Improvements in Transformer Connections, of which the. folldwing is a specification.

My invention relates to the gradual regulation of an alternating voltage by means of a transformer and a regulator, and has for its objects the provision of a method of operation -and means for carrying out the method whereby the entire transformer may be at all times in service and'where the number of leads from the transformer is small.

It is common to regulate an alternating voltage by employing a transformer having at least on winding divided into groups of turns,- and an induction potential regulator. The passage from one step to the next, that is the changing of the voltage as one side of the line is changed from one grou to the next, is made gradually by the'aid 0 a regulator; generally the gr'caups are composed ofapproximately the same number of turnssince the regulator is required to furnish a voltage at least equal to that of the largest group. In the devices in use prior to my invention, those groups whichat any particular time were not in effective use, that is not carrying load, when left connected to the rest, of the transformenhad' induced in them a voltage higher than that on the line; this groups havin at times reached a dangerous value; to prevent accidents it has been common to prd vide special means to disconneet'frpm the rest those groups which are'not in active use. :In these devices there are a'l'arg number of leads.

Broadly my invention consists inthe; provision 'of a method of operation whereby all the groups of the transformer'windin are at all times in active operation and are silly ject to no voltage above that of the line and where the re ulation is accom lished by the. regulator an by reversing reiiitively to-the rest of the winding, certain groups which with the regulator produce at time's-a zero effect, andin the provision of an apparatus for carrying out this method.

With my invention the groups may contain any number of turns, but I prefer to use different numbers of turns in order to re ace the number 0t leads; this may be done very advantageously and preferably by using groups, the numbers of turns of which form a geometrical series.

My invention is'not limited to the division of one winding only of a transformer into groups; where, however, but one winding is divided into groups that winding may be either the primary or secondary. In any case in maximum voltage and load the regulator needs only to equal thesmallest transformer group withw'hich it is gcooperating.

The single figure in the drawing, which forms a part of this specificatiOm-showsdiagrammatically a transformer, one winding of which is formed in three 'groups of turns, and a potential regulator in connection therewith.

It will, of course -be understood that the transformer is not necessarily limited to hav mg three groups of turns,but that any number of groups may be used so long as there is a' plurality. Also, it is not necessarythat all the groups have a common core and be suppliedby a singleline.

The transformer illustratedhas one *winding' divided into three groups 10, 2w, 411;, the

group 2w having twice as many turnsas the group w and the group 4w having four times as" niany turns.- In addition to the transformer a potential re ator ris used. Any regulator which may adjusted from max mum in one direction through zero to maximum inthe opposite,direction may be used. I h vs shown diagrammatically a common in ing one win :nglan'd 'iqarlllwrta'oneivinding of the transtorinertand the-"ether winding adapted to connected iii-various wayswith that other-winding?- of the transformer which is divided into groups; This connectiong'of the inducting. winding pfthe induc- I tion regulator ieiiitable? whn the undiprimary thereof; other pdnnectinns of the inducing winding of'thoeregulaton may be more desirable at times, asforexam lewhen the undivided winding is the seeon ary. Y

The wires 1 andt2 convey current-tolor from-g the, divided," winding according to whether this-winding is the primary or-the secondary of the transformer; -One of these wires '21s attached direct to the group-4w.

Tothe other side f this rou is attached the lead 3, to which lead e t ree switches 4, 5 and 6 are connected. These; switches at various times connect the lead 8 to the convid'ed Winding of the .tral fi ioijmris the necting leads 7, 8 and 9.. To'the group 2w group -w is permanently, connected. to one are connected the leads 10 and '11; one side of this group may beco-nnected' through the lead 10 and lead 14, or through this lead and the switch 13,'to,the connecting lead 8 and the group 10; the lead 11 is permanently attached to the connecting lead 7. One side of the side of the regulator 1', the other sides of the two respectivelybeing permanently connected to; the connectinglead '8 and to the connectin leads 9 and 14:. The connecting leads 7, 8 and-9 'Inayat various times bec0n-.. nected'to the wire 1' through the switches 15, 16-, 17. The winding of the transformer which I have shown as divided into groups may be regarded as the secondary winding supplying current to the wires 1 and- 2. To raise the voltage on these wires from zero to maximum the operation may beas follows:

The switches 4, 13 and 17 are closed'and the regulator is so set that it aids the group 10-. The -'circuit from 'wire .2 is downward through"th e group 4112, along-the lead 3 to the switch 4, through the connecting lead 7 to the lead 11, and thence upward through the group 2w, down through the lead 10 to the switch 13, from thence upward through e i the winding w andfrom there through potential regulator and theswitch 17 'to the wire 1. We have assumed that the re ulator is adjusted to give its maximum v0 tage in such a direction at any particular instance as to aid the group 10. Hence we have the group 4w opposed by the regulator and the groups to and 2w, the combined effeet of the last three equaling the'efiect of the roup 1w with the result of no current on the wires 1 and 2.. Sup ose now that the regulator be so adjusted at it is neutral:

the circuit remains the. same, but now the.

regulator r is neither aiding nor opposing any group of windings and the group 4w is now opposed by the groups 210 and 112 only; there is an effect on the wires 1 and 2 -of-a group having a number of turns equal to the difference between the number of turns on the group 411; and the sum of. the turns of the groups 2w and w, or Now adjustthe regulator so that itopposes the group 112; the circuit is still the same, but now .we have the group 420 aided by the regulator, which is the equivalent of agroup having the same number of turns as the group '10, and opposed by the groups 2w and 20, resulting in an effect on the .wires 1 the wires 1 and The switches 13 and 17 and 2 of a-single group having-twice the number of turns'ns the group w.- At this stage the switches 12 and 16 maybe closed, short circuiting the group 'w and the ltgll lator r, since these two equal-and oppose each other. there is .no change in eil'ccton the switch 12' to the connecting may now be opened. By tracin; .he new circuit, it will be seen that we nave the grou'ps 4w and-w opposed by. the group 2w ,and the regulator. with the same efiect on .the Wires 1 and 2 as beforei'the changing of the switches. The regulator may now be changed to zero and to maximum in the 0pposite direction, the effect on the wires 1 and 2 passing gradually from the effect-of 2w turns through 3w turns to 4w turns. After reaching this stage the switches -5 and 15 may be closed, short .circuiting groups 2w and w and the regulator, the sum of the effects of which is equal to zero, and the switches 1 and 16 opened. By operation of the regulator the efi'ect now passes from 4w to 5w and. to 6w. The

switches 13 and 6 may now be closed and 5 j and 12 opened, after which the regulator may' again be operated and the efiect changed from 6w to 7w and to 8w, the maximum for the apparatus, all the groups and the regulator assisting.

The operation of the switches'and regulator to obtain the variousvoltages may be easier understood from the following, the signs representing the various coils and the regulator, at any particular instant, as assistlng or opposing the gr'ou and the sums showing the results on t e wires 1 and 2 in efi'e'ctive turns:

closed above, namely, the reversal of thegroup or groups and the regulator whose combined effect may equal zero, relatively to the other groups of the transformer wind mg.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1; In combination, groups of transformer windings, the numbers of turns of the various groups farming approximately a geometrical series," a potential regulator, and means for reversing the relation of the smallest group and the regulator to the other groups.

2. In combination, groups of transformer windings, the numbers of turns of the various groups forming approximately a geometrical series, a potential regulator, and means for short circuiting the smallest group and the regulator and for reversing their relation to the other groups.

3. In combination, two groups of transformer windings having dliferent numbers of turns, a potential regulator, and means for reversing the relation of one group and the regulator to the other group. I j

4. In combination, groups of transformer windings, the numbers of turns of the various groups forming approximately a geometrical series, a potential regulator, and

means for reversing the relation of the smallest group and the regulator to the other groups and for reversing another group.

5. In combination, groups of transformer windings, the numbers of turns of the va-' rious groups forming approximately a geometrical series, a potential regulator, and means for short circuiting certain of the groups and the regulator and. for reversing their relation to the other groups.

6. In combination, atransformer winding, a potential regulator, and means for reversing the regulator and a part of the winding relative to the rest of the Winding.

tial regulator,

7 In combination, a transformer winding, a potential gilator, and means for short circuiting the regulator and a part of the winding and reversing their relation to the rest of the winding.

8. The method of gradually regulating or varying an alternating voltage by a potenand a transformer winding connected in series, which consists in changing the voltage by means of the regulator until the effect produced by the regulator and a part of the windings equals zero, then reversing this part of the winding and the regulator relatively to the rest of the winding, and again changing the voltage by means of the regulator.

9. The method of gradually regulating or varying an alternating voltage without opening the circuit by and a transformer winding connected in series, which consists in changing the voltage by means of the regulator until the effect produced by the regulator and a part of the winding equals zero, then short circuit- .ing this part of the winding and the regulator'freversing them relatively to the rest of the winding and the line, and opening the first connections of the first mentioned part of the windings and the regulator to the rest of the winding and the line, and again changing the voltage by means of the regulator.

In witness. whereof, I have hereunto setmy hand this 22 day of July, 1911.

KARL SCHM DT.

\Vitnesses RICHARD NEUMANN, CHRISTIANO LARLI.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.

a potential regulator, 

